Patent GB-832202-A (GB)
Title: Continuous flow electrophoresis
IPC: G01N27/447
Filed: 1956-04-12
Abstract: 832,202. Electrophoresis. BIER, M. April 12, 1956 [April 15, 1955], No. 11119/56. Class 41. A method for the continuous concentration, fractionation, or purification of colloidal components from their suspension in an electrophoretic cell enclosed by two semi-permeable members 4a, 4b and traversed by an electric field, comprises continuously feeding the suspension into one end of the cell at 5, concentrating a colloidal component at one membrane 4a, continuously withdrawing the concentrated fraction at the other end of the cell at 8, reversing the direction of flow of the remaining suspension in the cell to return it in countercurrent to the incoming suspension, from which the remaining suspension is separated by a membrane 7, and continuously withdrawing the remaining suspension from the feed end of the cell at 6. Colloidal solution to be treated is delivered continuously at 5 into a compartment 1 separated by the membrane 7, which is semipermeable, from a compartment 2 having an outlet 6, the cell being immersed in a buffer solution in which are electrodes connected to a source of direct current. The cell comprises two frames 9, 9<SP>1</SP> bolted together and between which are clamped the membranes 4a, 7, 4b and gaskets 13, 13<SP>1</SP>. The inlet 5 and outlets 6, 8 each comprise a stainless.steel tube 10 leading to a passage 11 from which a number of narrow apertures 12 lead into the cell. In concentrating, the pH and salt concentration of the buffer and the polarity of the field are adjusted so that the colloid migrates to the diaphragm 4a, whereby concentrated solution leaves at 8 and depleted solution at 6, the degree of concentration being controlled by regulating the rates of outflow at 6, 8. The rate of admission at 5 is adjusted with respect to the mobility of the colloidal particles in the buffer and to the intensity of the electrical field so that all the particles will travel the distance from the membrane 7 to the membrane 4a in the time taken for the solution to flow through the compartment 1. In separating two colloidal components in a solution, the pH of the buffer is made intermediate the isoelectric points of two components, one being fully recovered at 8 (but mixed with the other component) and the other being partially recovered in pure form at 6. Alternatively, both components may be made to migrate to the diaphragm 4a, the liquid flow being adjusted to the maximum concordant with the complete elimination of the faster component at 8. In either of the above examples the cell may be operated in inverted position, solution entering at the bottom of the cell and leaving at the top and bottom, e.g. where the specific gravity of the colloidal particles to be separated is less than that of the dispersing medium, e.g. where the particles are rubber latex. The buffer, which may be circulated or periodically replaced, may be the solution being treated. In one example, hemoglobin was concentrated employing a barbiturate buffer and a voltage of 4, the flow rate through the cell being 1 ml. per minute. In another example, bovine hemoglobin was separated from bovine serum albumin employing an acetate buffer, voltages from 1 to 5 and a flow rate of 0.6 ml./min. A number of cells may be connected in a single frame, the membrane 4a of one cell being the membrane 4b of the next, and the inlets 5 may then be connected in parallel, or the outlets 6, 8 of one cell may be connected to the inlet 5 of the next. Reference has been directed by the Comptroller to Specification 505,753.